In the News: West Nile Virus and Pregnancy

Giving Birth with Confidence brings to you a new series called "In the News" where we will touch on health-related topics that are buzzing in the media and how they relate to pregnancy, birth, breastfeeding, and early parenting. Look for this series to appear periodically on the blog.


As it does nearly every year, news of a string of West Nile Virus (WNV) cases has popped up. According to a report from the U.S. Centers for Disease Control (CDC) on CNN yesterday, "cases of West Nile virus are up 25% over the past week and are expected to rise further over the next several weeks." At Giving Birth with Confidence, we share this information not to increase your anxiety during pregnancy (pregnancy is a normal experience for your body!), but to provide information on maintaining health, safety and regular activities in spite of alarming media reports. We also aim to provide information from sound, evidence-based sources to help families wade through the overload of information available on the internet.

The following information and guidelines on WNV are reproduced with permission from the Organization of Teratology Information Specialists (OTIS), a non-profit organization dedicated to providing accurate evidence-based, clinical information to patients and health care professionals about exposures during pregnancy and lactation. While the information provided here is accurate, it does not take the place of medical advice. If you think you may have West Nile Virus or have additional concerns, contact your care provider.

What is West Nile Virus (WNV)?WNV is a virus that can infect humans, birds, mosquitoes, horses and some other mammals. It is commonly found in Africa, West Asia and the Middle East. Since 1999 WNV has been found in the United States.

You cannot get WNV from birds or horses. If an infected mosquito bites a human, the human can become infected. The incubation period (the time from bite to the start of symptoms) is usually 2 to 14 days.

What are the symptoms of WNV?Most people infected with WNV will have no symptoms or very mild symptoms. About 20% of infected people will develop more serious symptoms of WNV. These symptoms include fever, headache, being very tired, body aches, swollen glands and sometimes a skin rash on the trunk of the body.

Less than 1% of infected people will develop severe infection that leads to swelling of the brain or swelling of the area around the brain and spinal cord. These symptoms include headache, high fever, neck stiffness, confusion, tremors, convulsions, muscle weakness, paralysis and coma.

Generally, symptoms of WNV last only a few days but can last up to two weeks. Symptoms of severe WNV may last several weeks and some people may experience longterm illness.

How is WNV treated?There is no specific treatment for WNV. Pain relievers such as acetaminophen may help relieve some minor symptoms. Individuals with severe WNV infection may need care in the hospital. You should contact your doctor if you think you have developed WNV.

I am pregnant. How do I prevent mosquito bites?Pregnant women should protect themselves when outdoors by using a mosquito repellant that contains DEET or picaridin. With proper use, these products will not increase the risk of birth defects or other pregnancy problems.

It is suggested that pregnant and breastfeeding women follow the same recommendations that are given for children's use of DEET. Wear long-sleeved shirts and long pants, a hat and shoes with socks. Apply the lotion to the hands, neck, face and wrists, then spray your clothing and hat. Since these products can be absorbed, covering only small areas of skin with DEET is advised. It is essential to use DEET or picaridin if outdoors during mosquito's active time, from dusk through dawn. Try to limit the time you spend outdoors when mosquitoes are most active.

To further decrease your exposure to mosquitoes, frequently change the water in birdbaths and outdoor water containers where mosquitoes might breed.

I am pregnant and have been diagnosed with WNV. Can this harm my baby?Very little information is available regarding exposure to WNV during pregnancy. There is one known case of a pregnant woman passing on the virus to her unborn baby. The baby was born with serious medical problems. However, it is unclear whether the problems were caused by WNV infection or by other factors. No other cases of babies being born with problems have been reported despite many pregnant women having evidence of WNV infection. More research is needed before we can say whether a baby may have problems if a mother develops WNV during pregnancy.

I'm breastfeeding. Can I use DEET or picaridin?Breastfeeding mothers must also protect themselves from mosquito bites by using DEET or picaridin. No reports or problems associated with using these products while breastfeeding have been noted. The application of DEET or picaridin while breastfeeding is the same as in pregnancy.

I've been diognosed with WNV. Should I continue to breastfeed?The passing of WNV through breast milk is still being researched through the Centers for Disease Control and Prevention(CDC). Infected infants and young children usually have mild symptoms and rarely developcomplications from WNV. In one case, a woman was infected with WNV after the birth of her child. The virus was present in both the baby and the breast milk. However, the child had no symptoms and remained healthy.

Because there are important benefits to breastfeeding and the risk for passing WNV through breast milk is unknown, the CDC recommends that women should not stop breastfeeding because of WNV infection. Talk with your pediatrician about continuing to breastfeed if you have a confirmed active case of WNV.September 2009.Copyright by OTIS.Reproduced by permission. Click here to see references used in this fact sheet.

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